Ultra high frequency electric discharge device



Nov, 30, 1948. J. w. LAFFEva-l-Yl lULTRA HIGH FREQUENCY ELECTRIC DISCHARGE DEVICE Filed oct. 16, 194s 2 Sheds-Sheet l Fig. 1

ULTRA HIGH FREQUENCY ELECTRIC'DISGEARGE DEVICE 1 Filed oct; 16, 19473,

' Nov. 30, w48. Ew.- LAFFER-'rv Sheets-Sheat 2 4 Figa.

TIME

FOCUS/N6 ELECTRUOE DIAPHRHG M Invnto'r: James M. Laffetg,

Attorneg.

Patented Nov. 30, 1948 UNITED STATES ULTRA HIGH FREQUENCY ELECTRIC DISCHARGE DEVICE .lames M. Lafferty,

General Electric Company,

New York Colonie, N. Y., assigner to a corporation of Application Uctober 16, 1943, Serial No. 506,501

' l2 Claims.

My invention relates to ultra high frequency electric discharge devices and, more particularly, to ultra high frequency electric discharge devices of the space resonant tyIpe employing velocity modulation principles.

In my copending application, Serial No. 477,065, filed February 25, 1943, now Patent No. 2,421,273, granted May 27, 1947, and entitled Ultra high frequency electric discharge system, and assigned tc the same assignee as the present invention, I disclose an ultra high frequency oscillator Iof the reflex velocity modulation type in which a space resonant cavity is pro-vided. The operating frequency of the device is controlled either by mechanical means, which adjusts the position of a tuning diaphragm, or electrically by controlling the potentials of retarding and repelling electrodes with respect to an anode structure. My present invention is direc-ted to certa-in improvements in an ultra high frequency electric discharge device of this type.

It is an object of my invention to provide a new and improved ultra high frequency electric discharge device or oscillator of the velocity modulation type.

It is another object of my invention to 4provide a new and improved composite electrode structure for an ultra high frequency electric discharge device.

lit is a further object of my invention to provide new and improved means for cooling the anode of a reflex type velocity modulation discharge device.

It is a still furtherI object of my invention to provide a new and improved method of forming a cavity resonator.

l'.-t is still another object of my invention to provide a new and improved anode structure for an ultra high frequency electric discharge device of the space resonant type.

In accordance with one aspect of my invention, I 'provide a new and improved electric discharge device employing velocity modulation principles an-d including a metallic enclosing envelope wherein a cylindrical heat conducting member disposed within the envelope is in thermal contact with, and mechanically supports a disk-type anode structure having a centrally located apertured space resonant cavity, the anode structure serving to support a plurality of associated electrodes by means of insulating cylinders hermetically sealed between arms extending from lthe anode structure and they electrodes.

A further feature of my invention relates to an improved anode structure of Ithe cavity resonator type and having a 'deiomnable diaphragm constituting one boundary of said cavity, the diaphragm and a surface of the anode disk forming a half wave choke included lin the cavity resonatcr.

A still further feature of my invention relates to the construction of a reentrant type. cavity resonator wherein a soft malleable metal member, formed to the exact shape of the cavity, is

i eleetroplated with a good electrically conductive metal to form cavity walls of desired thickness, the soft metal being thereafter removed by means of a suitable acid.

For a better understanding of my invention,

reference may be had to the following description taken kin connection with the accompanying drawings and its scope will be pointed out in the appended claims. Fig. 1 is a longitudinal view, partly in cross section, of an electric dis-charge device of the velocity modulation type built in accordance with my invention. Figs. 2 5, inclusive, are detailed cr-oss sectional views of this discharge device. Fig. 6 is a modification of the anode structure used in the device shown in Fig. 1 and illustrates steps in the method employed for forming a cavity resonator. Fig. 'l is a cross sectional view of an anodestructure employing the cavity resonator of Fig. 6. Fig. 8 is an enlarged diagrammatic sketch showing a possible distribution of equipotential lines of force in the retar-ding and reversing regions of the discharge device, and which also illustrates the paths of electrons having different amounts of energy and the iprobable paths of such electrons. Fig. 9

shows the manner of variation of the radi-ofrequency or the ultra high frequency modulating voltage which appears across the modulating gap within the space resonant cavity.

Referring now to Fig. 1, my invention is there illustrated as applied to an ultra high frequency electric discharge device comprising an enclosing envelope I, preferably of rigid construction, comprising a metal having a low coefficient of thermal expansion such as Inval', and which denes at least in part an evacuated space within which are positioned the various elements or electrodes described hereinafter. The envelope I is supported by and sealed to a base member 2 which comprises a flanged metalIicpart 3 upon which the lower end .of envelope I is seated and to which it is secured by a suitable sealing means, such as a solder 4. A flanged member 5, having a portion opposed to flange 3, is attached thereto in any suitable manner, as by welding. A plurality of prongs or terminal posts G-IIJ, inclusive, are

.being connected between andere supported by an insulating part I2 of base member 2 in insulated relation and serve as externally accessible contacts for the electrodes of the discharge device. Of .the aforementioned ve terminal posts, four are visible in Fig. 1, terminal post In being shown in Fig. 2.

An orientation `prctuberance for guiding the insertion of base member 2 and the terminal posts into an associated socket is provided and is preferably centrally located. The orientation" yprotuberance may comprise a tubular extension I3 of insulating material formed .integral Withpart I 2 and having a central opening kthrough which extends a concentric transmission line comprising an inner conductor I4 andan outer tubular conductor I5 which is sealinglyattached to the top surface of part 2 fbylmeans of ametallic sleeve or eyelet I1 o any suitable material, such as fernico. The transmission line just described is supported near its upper end by means of =asealing insulator i8 :within sleeve I1 and w-l'richl not only serves as mechanical support and positioningk means for the .inner conductor I4, but alsoserves as 4the-means for sealing these elements to maintain a desired degree of evacuation witin-the envelope of :the discharge device. Within the envelope I and preferably centrally located-near the lower part of the defined space, I provide a thermionic cathode which may be ci the indirectly heated type comprising a metallic cylinder ISL-preferably coated on the exterior of the upper closed end with an electron emissive material, `such as an alkaline earthmetaL-to serve as va 'sourceoi electrons. A filament or heating element 29 is centrally positioned within the cylinderV I -and is supplied with` energizing current through a pair of conductors 2l 22,' conductorl 2 I one end of filament 2li and terminal post 1-and conductor 22` (shown in Fig. L2)* being connected `to `the terminal p ost l0. The other end 23 ofl-ament 20 is Welded directly tczthe'outer surface of metallic cylinder I9 at its lower extremity. An electrostatic f shield compris' rgjananged cylinder 24 is We1ded-to thev ert'erior surface cfu-cathode cylinder I9 and supp'ovt'edmfrcm ametallic disk 25 by means of a pluralityof small wires :26, welded between parts Z'Qarrcl- 25. Conductor '22 may be welded directly to disklz.

An, anode. structure definingA a lspace resonant cavityorregionds provided comprising a substantially 'disk-shaped, metallic part. 21 Y andV is preferably constructedof an iron blockwhich is lightlysand-blasted and 'then plated` with a suitable conductive material, such as copper. Thereafterv the block `isheated in an atmosphere of hydrogen to melathe copper to increase its conductivity.the sand-blasting .operation serving to prevent puddling of the copper to assure a unifor-rn vdistribution of thecopper` after theheating. The anode block. 21`.is supportedy byand thermally. connected. to .acylindric-a'l heat conduliugmelnber 28forrned of. a suitable metal having/a low. cceii'cient of thermal expansion, suchas Invar, the block 21 being attached. thereto by spot welding. The .heat conducting member may be, corrugated, as shown,l and havev an outerdiameter. such.Y that it slips within the envelope .i ymaking.,thermal contact therewith. at each corrugation.. At its lower end member 28 ts .around the .upperend of base 2,. being attached` thereto as bywelding At the central. part of the block 21, there is provided A,a central opening; defining a., space resonant region or cavity 29. The detalls of the anode structure are shown in Figs. 4 and 5, the former of which is a plan view and the latter of which is an enlarged cross sectional view. The block 21 is provided with a plurality of recesses 3G into which extend an equal number of radially extending metallic arms 3l attached at their inner` endsgto the.blockv 21. An additional recess 32v is provided which is in communication with the space resonant cavity 29 through a radial opening 34, preferably of circular cross section, and Whichhouses one end of a concentric transmissionY line 35, shown in Figs. 1 and 2.

As, ameans fordening one boundary of the space resonant cavity 29 and also for providing an entrance and tron beam, member 31 is provided preferably constructedof metalpsuch as copper, and which is adaptedI to be seated in a recess in the bottom face of block 21. The member 31 includes a conical part 38 having a tapered. .aperture 3B thrgugh-which the lelectron beamnpassesand whichgrdenes withone` boundary of the space resonant cavity 29 Aa velocity `modulating gap 4D for the electrons constituting thebearn.

In order. tocontrol the natural lirequencyby controlling the physical. vdimensions .of l.thespace resonant Icavity 28, a deformablemember, such as a flexible nietalliodiaphragm 41, is provided, whichat its outer edge, is seatedupona circular iiangedz, extendinguupwardly from the topsurface. of block 21; to .constitute one .boundary of the .cavity ,253.` Thel diaphragmv 4I `is .provided with a `central aperture 63,to. afford a communieating path betweenthe cavity .and the Velectron retardngand reversing .regions described hereinafter. The radial dis-tance-fromthe central openingdnanode ,blockf21 to the. .inner surfaceof the circular ,flange-@Lis madel approximately .equal to-a half .wave-.lengthatsthe desired operating Y v Y ,electric discharge `device so that the..Yoliaphragmfill` `,and the top'suriace of block 21 ;betwee n-the resonantlcavityr-ZS andange 42 formyafsectiqn of. radialtransmission lineof a length such that the short-circuit at one end, constitutedyby-theflange d2, is reproduced to appear as afyer-y low-impedance 'at the inner end ofi-this-.section of-l radial transmission line. The disk 4I and the upper surface of Yblock 21` are providedgwith Iaplurality of `corresponding and concentric grooves y4'.l,;the function -of whichis pointed out in `detail hereinafter.

Returning now to Fig. 1, control lelectrode means are provided forestablishing electronrepeiling yandfretardingelectric elds vand which may take the form of a pair of disks 46 .and 41, thelatteridiskibemg provided with central aperture :.49 toitpermit; the. passage of l electrons therethrough .-into. theA .region defined `between disks 46 and 41 or to produce the-proper electric fields structure, likewise isprovided with radially extending arms'48. In-order to insulate the respective velectrodes from the anode block 21, as well as to support these `electrodes from anode yblock ZI'and'mindirectly from heat conducting member 28,2. plurality of insulators 5D of ,a suitable materialj,such as glass, arehermetically sealed to the .arnesi and .48...

InA order todmprelss suitable potentialsvon the disksl 46' and 41, a pair of conductors 52 and directing structure for the elec- 53, `as shown Iin Fig. 3, are provided, which extend respectively through lapertures 55 and 55 of anode disk 21 andare connected to cross conductors 52', 53' conductively `joined respectively to the above-mentioned disks. Conductor 52 may be connected to a central terminal post 56 attached to disk 16, while-conductor 53' may be connected to the' terminal 51 attached to the edge of the disk 11. Also connected between conductorsr 52 and 53 and aconductor 58, soldered or welded at` its lower end to an aperture 59 in the anode block 21, are a pair of fusible conductors Bil which may comprise gettering means for the discharge device after it has been evacuated.

`To focus the electrons emitted at the upper end of cathode cylinder` i9 a focusing electrode means' are employed, which may comprise a cylinder Al supplied with a plurality of radially extending arms 62 embedded in the insulating cylinders 5i). A suitable negative focusing potential may be impressed on cylinder Bl by means of a conductor 63 which is attached to an additional arm -64 extending radially outwardly from cylinder lBI and which is connected to terminal post 6 through a lead-in wire 55.

In order to derive ultra high frequency energy fromv cavity 29, a curved ultra high frequency concentric transmission line 35 extends from that cavity to the base member 2 to facilitate external connection to the device. The concentric trannmission line comprises an inner conductor 61 and an outer-tubular conductor 58 separated by a pulverized insulator, such as a vitreous material 1b9 which may be quartz. The inner conductorl61 extends into the cavity 29 and serves as an output electrode means and may take the form of a loop 10, whereby the transmission line is coupled to the cavity. The lower extremity of the transmission line comprising conductors 61 and 68 is provided with an adaptor assembly which comprises a recessed metallic cylinder 1| supported at the lowerl end of the outer conductor 68. Within the recess of cylinder 1l there is provided an-adaptor for the inner conductor 61 which comprises a metallic part 12, in turn being provided with a recess at its lower end which engages the upper end of inner conductor I4 of the transmission line supported within the tubular extension i3 of the discharge device. The outside diameter of cylinder 1l is chosen so that the adaptor assembly snugly fits the inner` surface of eyelet l1.

Io assure good electrical contact between cylinder 1l and eyelet I1 and between conductor I4 and part 12, respectively, the outer surfaces of cylinder 1l and the inner surface of part 12 are tinned prior to the assembly operation. After assembly of the elements in the positions shown in Fig. 1, after .the application of heat thereto, the tin forms a rm connection between the elements, that is, between cylinder 1l and the inner surface of eyelet l1 and between conductor i4 and part 12, respectively.

As a means for mechanically controlling the form and position of the diaphragm 4l, an externally accessible actuating means is employed for exerting different amounts of pressure thereon, thereby controlling the dimensions of the space resonant cavity 29. This means may comprise an assembly supported by the flat top of the envelope I and may include an actuating rod constituting a vertically adjustable or positionable member of the actuating means. Rod 15 is connected to the diaphragm 4I by a pair of vertical wires 11B- and 11 and a cross piece 18, the

latter being welded to rod 15 and wires 15 and 11 being welded to cross piece 18. At their lower ends, the wires 16 and 11 are seated in one of the grooves 44 in the upper surface of diaphragm 4| and may be permanently attached thereto, as by soldering. Alternatively, instead of the wires 1.6, 11 being soldered or welded to the diaphragm 4l, these rods or wires may be seated in an annular groove provided in the diaphragm and the diaphragm formed to have a resiliency tending to restore itself to an upward or vertical position whereupon the diaphragm is maintained in contact with rods 16 and 11. In such instance, the control of the form of .the diaphragm is accomplished by the amount of downward vertical pressure exerted thereagainst. Surrounding the vertical rod 15 is a hollow tuning screw 30 which is welded or brazed around the top of rod 15 to form a vacuum-tight seal. At its lower end, the hollow tuning screw 8G is welded or soldered to a metallic bellows 8l sealed to.the inner surface of envelope i to provide a sealing structure of deformable character for the upper portion of the envelope.

Above the envelope l and in an externally accessible position, a micrometer adjustment means 82 is provided to actuate rod 15 whereby, upon actuation, the rod 15 is moved to position the diaphragm M in minutely determinable degrees .to obtain a desired control in the operating frequency of the device. Preferably, the rod 15, cross piece 18, wires 16, 11, tuning screw 8i), and micrometer 82, are composed, similar to envelope l and member 28, of a metal having a low coefficient of thermal expansion, Invar being well suited for this construction. So constructed, the device experiences little change in operating frequency asA the operating temperature varies.

Fig. 2 is a cross sectional view of the discharge device shown, in Fig. 1 along the lines 2-2 and represents the arrangement of some of the conductors, particularly the connections 2l and 22 to the cathode. Also shown in this view and in the vertical view in Fig. 1 is an exhaust tubulation 84 for producing a desired vacuum within the electric discharge device. Fig. 3 is a cross sectional view of the discharge device shown in Fig.' l along the line 3-3 and represents the arrangement of other conductors, particularly .the connections to the gettering means llill. After the discharge device has been exhausted through tubulatio-n dit and later sealed at its lower tip in the usual manner, conductors 52 and 53 are connected together externally and voltage impressed between' conductor 58 and conductors 52, 53 to flash the vaporizing material supported about fusible conductors Si! in order to absorb occluded gases.

Referring now to Fig. 6, I have thereI shown a modification o-f the cavity resonator employed in the anode of my electric discharge device and have illustrated certain steps in the process of forming this cavity resonator. In constructing the cavity resonator 36, I form a pellet 81 of a soft malleable metal, such as zinc, to the exact shape of the cavity, stamping the pellet to this shape by means of a punch and die. The stamped pellet is then electroplated with a suitable metal having high electrical conductivity, such as copper or any other metal in the rst group of the periodic table of elements. Inthe step of electroplating the zinc pellet 81, an electrode 88 is attached to one of the Walls of the pellet, in the case of the particular pellet shown, to a side wall. After the pellet has been electroplated until a deposit of a desired .an excitationgof .the

startingoperation,

thicknessis obtained softhatrwallseof Athe cavity resonator. v88 :have a. sufficient. strength, -the electrodedl :is removedY and small. concentric holes, corresponding to thehole-JISy shown in Fig. 5, are drilled vthrough the conical -section ;.f38'y and the upper .wall 4| ofthe cavity resonatord Thereafter,.the composite structureis placed in a bath of 'suitable acid, such as concentrated hydrochloric acid, tofremove the soft metalpellet- 81, leavinga thin shell of the hardmetal-havi-ng .the exact form of the resonant. cavity; To y this end, the-metal of the pellet 87 should lie above hydrogen in the electromotive series-while the `metal forming the Walls of resonator 88 shouldflie -below hydrogen -in the electromotive-'series By this process, the intricate machining operationsre quired in the cavity structure shown in Figs. l and zare avoided, While exaotialignment. of the holes through yvvall 4l" and the cone 38'.-is obtained. Moreover, any desired intricacy of the `Aref-:ntrant cone design may -be obtained --with ease andia- Unity;

InfFig. 7,1 have shown a modicationfof-the anode block 2T used in conjunction with the cavity resonator SS-formed in .accordance with .the processy described above. In Figs. 6 and 7, elements 'correspondingtov elements illustrated and described in Figs. l and-5 are designatedbyxthe primes of corresponding reference numerals.- The block .272 is -providedwith e, central openinghaving a shoulder portion 89 upon which the cavity resonatoris placed;- The opening formed 7in therside wallofresonator 85 .when electrode-88 ,is removed provides. a `means 1for introducing vthe coupling loop .13' at-the -end of the concentric transmission linevcomprisinginner conductor 3l andouter tubular conductor 68,.

The operation of the embodiments of my invention described Vabove will be. considered with particular reference to Fig. 1 :and the-schematic arrangement of certain of -theelectrode Aelements shown. in Fig. 8,lwhen the device is'operating as Generally` speaking, the electric .discharge device is of the velocity modulation-type wherein theelectrcn beam isvelocity modulated periodically so` that successive groups of .electrons are-alternately'accelerated and decelerated, tendof .a .unidirectional potential impressed across .the

anodastructure ...comprising block. 21 .and'natl'i-ode cylinder I3. The electrons ofthe electron--beam initially assumes.. Velocity-determinedbythe ac celere-tingl potential impressed on .the anodestructure. A negative potential :with respect to t-he cathode-cylindel1 .IQ is impressed on A,the focusing cylinderri which tends torestrict :the size of ithe electron. beam, conningit toa relativelyvv small transverseareain order that a largepercentageof .the .electrons A.passthrough the l.space resonant cavity A29 through the conical .part38. `Assuming cavity 29 byvirtuefof sporadic motionof .theelectrons ltherethrough during; .the

cavity 29 is :set into :oscilla- 'before reversal and,

tionand there is-established.-across. the .modulatey ing `,gapl an alternating-ultra high frequency potential.. incident/to the electromagnetic eld within thecavity 29. By virtue ofthe alternating nature .of this potential, electrons which are vin ihefeiectiveiregionof gap40 .during periods of time when the vdiaphragrnM is, positive with remodulating .gap 48,., Consequently, the Yelectrons after traversing thespace resonant cavity 29- pro-v ceedthroughaperture 43. of diaphragm 4I .into the region of the eldproducedby the focusinsand retardicg electrode. .41, which. may ,be maintained at a negative potential with respect. .to the anode.

sentthe conto-ur ofthe electric lines of force resent the corresponding Vdirection -of thejmage netic component of electromagnetic field during the saineV half cycle. During a -hal-f cycle of opposit-e-polarity, the electric component and the travels a greater distance within.' the vicinity. of ay zero potential line. Lastima-n electron -of fevenfgreater Velocity Ipro ceeds-in the direction of 4fthe.;repelling electrode .4 iandfenters the. negative fieldf produced. thereby,

undergoing@d reversal in the region of the negative potential electric viield.`

The .operating frequency ofrfan electric `discharge device may be controlledveitherfby controlling. .the `physical dimensions .off the space resonant cavityv 291er by controlling the voltage Vimpressed uponftheelectrodes,v including the voltage: on -the anode structure andthe voltagey on the electrodes:- vt5 Y, and j .4?. f Considering.l llrstzthe control :ois-the operating.'rrequencyfby virtue .of .the echange: in the :physical dimensions of, the cavity, the posi-.tion :ofthe diaphragm si icon-trois one? `lamine.aryf of :the cavity -and: consequently controls itsnatinal fr.ecuiency.y Ready-adjusts .mentot :the .position .of ,diaphragm 44 isohtained vby manipulation .of'thegmicrometer 82,-- It yas fillustrated, is .reversed been found that in electric discharge devices built in accordance with` the above described principles and construction, the operating frequency of the discharge device may be varied throughout a range of 6000 megacycles and that the discharge device has an effective and substantial power output when producing a wave having a wave length of the order of one centimeter.

The operating frequency, as stated above, may also be controlled by variation of the voltages impressed on the repelling electrode 46 and the retarding electrode 4l, in this manner controlling the transit time of the electrons in the beam and lconsequently controlling the phase of the chargedensity modulated electrons which are returned to the space resonant cavity' 29 with respect to the field thereof. By using this method of controlling the operating frequency, it has been found that an additionaly finer adjustment of range of 90 megacycles frequency control may be obtained. The above described construction of an ultra high frequency electric discharge device, moreover, is peculiarly adaptable for the production of discharge devices of exceedingly small size.

While I have shown particular embodiments of my invention, it Will of course be understood that I do not wish to be limited thereto since various modifications may be made, and I contemplate by the appended claims to cover any such modifications as fall within the'true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An ultra high frequency electric discharge device of the velocity modulation type comprising an enclosing metallic envelope, a cylindrical heat conducting member disposed within said envelope and in thermal contact therewith at a plurality of points, a disk-type anode structure supported by and in thermal contact with said cylindrical member, said anode structure including a centrally located, Aapertured cavity resonator, a thermionic cathode positioned below said anode structure, a disk-type repelling electrode positioned above said anode structure, and a plurality of insulating members hermetically sealed to all said electrodes supporting said cathode and said repelling electrode from said anode structure in spaced relation therewith.

2. an ultra high frequency electric discharge device of the velocity modulation type comprising an enclosing envelope, a base member supporting said envelope, a cylindrical heat conducting member in thermal contact with the inner surfaceof said envelopeand supported by said base member, a disk-type anode supported by and in thermal contact with said cylindrical member, said anode including a centrally located, apertured cavity resonator, a thermionic cathode positioned below said anode structure, an apertured retardin-g electrode positioned above said anode structure, a repelling electrode positioned above said retarding electrode, each of said anode, cathode, and electrodes having a metallic arm extending outwardly from the active surface thereof, a cylindrical insulator hermetically sealed to said arms supporting said cathode and electrodes from said anode and maintaining said anode, cathode, and'electrodes in spaced relation, means within said base member whereby operating potentials may be impressed upon said electrodes, means connected to said resonator for tuning said cavity resonator and externally accessible actuating means for said tuning means supported by said envelope.

3. An ultra high frequency electric discharge device of the velocity modulation type comprising an enclosing metallic envelope, a base member supporting said envelope, a cylindrical heat conducting member in thermal contact with the nner surface of said envelope and supported by said base member, a disk-type anode supported by and in thermal contact with said cylindrical member, a plurality of electrodes supported by and in insulated spaced relation with said anode said electrodes including a cathode for producing an electron beam with said anode, said anode including a cavity resonator and being providedwith an inwardly extending part through which the electrons may pass to enter said cavity resonator and which defines therewith a velocity modulation gap, electrode means beyond said anode for reversing the electrons after traversing said cavity resonator to cause said electrons to enter said cavity resonator and deliver energy to the electromagnetic field thereof, means within said base member whereby operating potentials may be impressed upon said electrodes, means connected to said resonator for tuning Asaid cavity resonator, and externally accessible actuating means for said tuning means supported by said envelope.

4. A composite electrode structure for an ultra high frequency electric discharge device of the velocity modulation type comprising, a horizontal disk-type anode `structure `defining an apertured cavity resonator, a thermionic cathode positioned below said anode structure, an apertured retarding electrode positioned above said anode structure, a repelling electrode. positioned above said retarding electrode, each of said anode structure, cathode, and electrodes having a metallic arm extending outwardly from the active surface thereof, an insulating member hermetically sealed to said arms supporting said cathode and electrodes from said anode structure and maintaining said anode structure, cathode, and electrodes in spaced relation, and a vertical cylindrical heat conducting member thermally and mechanically connected to said anode structure at its outer periphery.`

5. An anode structure for an ultra high frequency electric discharge .device of the cavity resonator type comprising a metallic disk having a circular, centrally positioned opening therethrough defining in part a cavity resonator, an inwardly extending apertured conical member extending across the bottom of said opening defining one boundary of said cavity resonator, a circular flange extending upwardly from the top surface of said diskat a radial distance from the circumference of said opening equal to a half wave length at theoperating frequency of said device, and a deformable diaphragm hermetically sealed across said flange constituting an opposite boundary of said cavity resonator and forming with said top surface a section of radial transmission line. I l

6. An anodestructure for an ultrahigh frequency electric dischargedevice of the cavity resonator type comprising a metallic disk having a circular, centrally positioned opening therethrough defining in part a cavity resonator, an inwardly extending, apertured conical member extending across the bottom of said opening defining one boundary of said cavity resonator, a circular flange extending upwardly from the top surface of said disk at a radial distance from the circumference of said opening equal to a half wave length at the operating frequency of said device, a deformable I "diaphragm `heririetically `.sealed across said flange constituting an opposite boundaryof. said cavity resonator and forming-with said top surface asection of radial transmission line, and pressure activatedmeans connected to said diaphragm for eiecting' controllable deformation thereof whereby the natural frequency of said cavity resonator may be controlled.

'lr-AnV anode structure for an ultra high frequency discharge device of the cavity resonator type comprising-a metallic disk having a centrally positioned openingdening in'part a cavity resonator, an entrance part for receiving electrons'and producingv a narrowly dened control .region within saidv cavity resonator comprising an apertured metal cone constituting one boundary of said .cavity resonator, a circular iiange extending upwardly from the top surface of said disk at a radial distance from said opening equal to a half wave lengthat the operating frequency .ofsaid de.vice, a deformable diaphragm connectedV acrossv saidflange. constituting an opposite boundary of.v said cavity resonator'and forming with said vtop surface asection of radial transmission line, and a transverse metal rod connected .to .theouter surface `of said diaphragm at a pointbetween. .said opening andv said iiange whereby differentamounts of, pressure may be exerted on said diaphragm to control the natural frequency of said cavity resonator. Y

8. An ultra high frequency electric discharge device of the velocity` modulation type .comprising an .enclosing envelope, a, heat conducting within4 said envelope and yin thermal contact therewith at a plurality of points, an. electrode. structure in thermal contact with saidheat conductingmember, said electrode structure includinga .cavity resonator, and. eX- ternallyY accessible means. for. ,tuning` said cavity resonator supported by said envelopesaid .envelope, saidfheat .conducting member and said tuningmeans `being formed. of ametal having a low coecientfof thermal 1expansion to .minimize variation in the operating frequency of said device with variation in the operatingl temperature thereof.

9. Anelectron dischargetdevice comprising an enclosing .envelope having `a base portion and a cylindrical metallic wallportiony a cylindrical heat conductive member within said envelope supported on said" base vmember and having thermal contact with saidlwall portion at a pluralityr of points,` a pair of electrodes-'disposed within said envelope; one of'said electrodesk comprising an anodesupported from said member by thermally conductive -means, and insulating means supporting the; other -f of saidV electrodes from said anode. Y

10. A cavity resonatorqcomprising a hollow metallic member,v having a* pairY of parallelowalls and 'aside walll integrally united withsaid' parallel walls, one of said parallel walls having' a'-cen trallyr positioned opening' therein; the: oi'l'lerr of ings, said one wall having said parallel Walls havingan inwardly extending cone-shaped part, said part terminating in a second opening aligned with the rst of said opena circular ridge therein concentric withsaid openings to permit'flexing of said one wall to vary the distance between said parallel walls. y

11. A cavity resonator comprising a hollow metallic member having a pair of parallel walls and a side Wall integrally united with said parallel walls, one of said parallel walls having a centrally positioned opening therein, the other of said parallel lwalls having an inwardly extendingcone-shaped part, said part terminating in a second opening aligned with the rst of said openings, said one wall having a circular ridge therein concentric with said openings to permit nexing of said one wall to vary the distancel between said parallel walls, said side Wall having an Aopening therein, and output electrode means extending into. said resonator through said opening in said side wall.

12. An ultra high' frequency electric discharge device of the velocity modulation type comprising an enclosed metallic envelope, a heat conducting member disposed within said envelopein thermal contact therewith at a. plurality. of points and substantially surrounding a plurality of electrodes, said electrodes comprisingl an anode supported by and in thermal contact with said meinber and including a centrally located.apertured cavity resonator, a thermionic cathode positioned below saidanode, a repelling electrode positioned abovesaid anode, and a plurality of insulating memberssealed toall of said electrodes supporting said cathode andsaid repelling electrode from said. anode in spaced relation therewith.

JAMES M. LAFFER'IY.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,201,271 DeForest Oct. 17, 1916 1,560,017 Cleland et al Nov. 3, 1925 1,817,680 Pratt Aug. 4, 1931 2,075,855 Kilgore Apr. 6, 1937 2,163,157 Samuel June 20, 1939 2,167,201 Dallenbach July 25, 1939 2,181,366 Edwards et al Nov. 28, 1939 2,190,511 Cage Feb. 13, 1940 2,225,447 Haeff et al Dec. 17, 1940 v2,227,372 Webster et al Dec'. 31, 1940 2,281,717 Samuel May 5, 1942 2,303,166 Laico Nov. 24, 1942 2,311,520 Cliiord Feb. 16, 1943 2,311,658 Hansen et al Feb. 23, 1943 .FOREIGN PATENTS Number Country Date 509,102 Great Britain July 11, 1939 Certificate of Correction Patent No. 2,454,970. November 30, 1948.

JAMES M. LAFFERTY It is hereby certified that errors appear in the printed specioation of the above numbered patent requiring correction as follows:

Column 9, line 7 8, claim 2, after the Word resonator insert a comma; column 12,

line 25 claim 12, for enclosed read enclosing;

and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Office.,

Signed and sealed this 21st day of June, A. D. 1949s [BML] THOMAS F. MURPHY,

Assistant ommz'ssz'oner of Patents. 

